1. Technical Field
The present disclosure relates to energy storage devices and, in particular, relates to capacitors and, more particularly, to a supercapacitor.
2. Description of Related Art
Nowadays, portable electronic devices (such as mobile phones, notebook computers and digital cameras) are becoming more multi-functional and becoming smaller, thinner, lighter, flexible, and even rolls up, to meet the rapid growth for modern market demands. However, the energy management development (such as batteries and supercapacitors) is still inferior. Therefore, fabricating superior lightweight power sources and greater flexibility remains a challenging task.
Recently carbon nanotubes (CNT) or graphene nanosheets have been used as electrodes for supercapacitors and batteries. However, most work is done in the conventional energy-storage device configuration (a separator sandwiched between two electrodes sealed in liquid electrolyte), which suffers two major drawbacks for practical applications. First, liquid electrolyte requires high-standard safety encapsulation materials and technology. Electrolyte leakage will result in harm to the environment. Second, the component parts are not integrated with each other and tend to move relative to each other under strong flexing which decreases the electrochemical performance and cycle life of the device. Currently, there are only two configurations that are manageable (button and spiral wound cylinder) for current energy-storage devices. However, their clumsy bulky shapes have limited their applications in the future advancements of thin and wearable electronic devices.
What is needed, therefore, is to provide a supercapacitor with an outstanding supercapacitor performance under highly flexible (twisting) conditions.